First, you'll want a set of the appropriate strap rings, which are compatible with Hasselblad V and others. And one way to get the highest quality parts at the lowest price is to buy them as part of a rotted Hasselblad strap. But they're also available as new product:
Optech sells straps and clips that go over those posts. Optech calls them Super Pro A or B which are 3.1 or 4.1mm respectively. The Optech versions are very reasonably priced - the connector ends are $9-10 at B&H if you already own an Optech strap. Like this https://www.bhphotovideo.com/c/product/153014-REG/OP_TECH_USA_1301022_System_Connectors_Set_of.html
If you don't have a strap already, you can get the strap plus connectors, just search for "Optech super pro strap." I don't know who sells Optech in the UK, but someone probably does.